Electric organ



Sept. 14, 1937. s. YAMASHITA ELECTRIC ORGAN Filed July 10, 1955 2Sheets-Sheet 1 INVENTOR.

p 14, 1937- s. YAMASHITA 2,093,223

ELECTRIC ORGAN Filed July 10, 1935 2 Sheets-Sheet 2 /NVENTOR.

Patented Sept. 14, 1931 UNITED STATES PATENT OFFl 2 Claims.

This invention relates to improvements in electric musical instrumentsand more particularly to an electric organ which comprises vibrators andmicrophones totally enclosed in a sound proof casing, tone and frequencychanging electric circuits with volume controllers, and loud speakers.

One of the principal objects of this invention is to provide a simpleand compact electric organ without pipe arrangements whereby musicaltones of any musical instrument, such as an ordinary pipe organ, aflute, a clarionet and the like, can be easily produced with a desiredvolume without disturbance from external noises.

It has heretofore been known that a small elec tric organ provided witha microphone and an amplifier for magnifying the microphone currentenables the reproduction of sound as loud as in a large pipe organ.However, when the amplification is comparatively effective, the howlingphenomena due to the acoustic feed back between the microphone and theouter sound sources may occur through the organ body with the resultthat the satisfactory operation of the organ becomes impossible.

According to this invention the howling phenomena caused by the incomingsound from the loud speaker, the other orchestra and chorus in the sameconcert room can be avoided and the volume of the musical sound can beeasily controlled gradually to any desired amount and tremolo is played.

In the accompanying drawings, Fig. 1 is a perspective view of anelectric organ embodying this invention; Fig. 2 is a diagrammatic viewfor 11- lustrating the arrangement of the electric organ shown in Fig.1, a sound proof casing being shown in'a longitudinal section; Figs. 3and 4 show electric connection diagrams embodying this invention andFig. 5 is a schematic diagram showing an electric connection of afrequency changer to be used in this invention.

Referring to Figs. 1 and 2, 0. indicates an organ 5 body, b designatesits keys or electric switches arranged on a key-board 0. According tothis in vention, the organ is provided with a sound proof casing i linedwith sound absorbing material I, such as felt. Arranged in the soundproof casing I are a sound producing element 3 and a microphone 4 whichis led to a tone changing device i2 through an amplifier 5 and lead wire8. The sound producing element 3 consists of a sound board 30, vibratoror a reed 28 attached thereon,

opening I! of the air chamber 3i formed by the sound-board 30, a spring35 holding the valve 33 -'in its closed position, and an electromagnet34 for controlling the valve 33, the operating coil of which being ledto'the corresponding switch I).

The electromagnet 34, the spring 35 and the valve 33 are so arrangedthat these parts may establish a magnetic circuit when the electromagnet34 is energized, thereby attracting the valve 33 to open the port I9 32is an inlet opening and I is an exhaust pipe which is connected to 1 asuitable exhaust fan or blower (not shown).

Assuming that one of the keys 6 is operated and the correspondingelectromagnet 34 is energized to open the valve 33, then the reed 29 isvibrated by the air current passing therethrough as indicated by thearrows. The sound energy caused by the sound producing member 3 isconverted into electrical energy by the microphone 4 and the energy isled out of the casing i through the lead wire 8 after being amplified bythe amplifier 5. The output side of the tone changing device I! is ledto a plurality of loud speakers i4, I! through an amplifier i3 and alsoto loud speakers l1, l8 through a frequency changer iii and an amplifier31. These electric parts may preferably be arranged beneath the soundproof casing i in the organ body a as shown by the dotted lines and thespeakers are selectively connected to the output circuit of theamplifiers i3 and 31 by inserting plugs p into Jacks 1 respectively. Ifdesired, only one common speaker may be connected to the output side ofthe amplifiers.

Fig. 3 shows the connection of the above described electric circuit moreexactly. The output circuit of the microphone 4 is coupled through atransformer 38 to the input circuit of the amplifier vacuum valve V1.This vacuum valve is provided with a potentiometer 39 by means of whichthe grid bias voltage thereof is adjusted to change the wave form of theinput voltage. 40 A vaccum valve V2 of the tone changing device i2 isconnected to the output circuit of the vacuum valve V1 through atransformer 4i. The input circuit of the vacuum valve V2 includes thesecondary winding of the transformer 4i, 3, variable resistance 40, anda variable condenser 42 which may be so adjusted that oscillationcurrent including desired higher harmonics can be produced in the outputcircuit of the vacuum valve V2 having transformers 2i and 2! in series.The secondary winding of the transformer 2i is connected to the loudspeakers i4 and i5 through the amplifier l3 having a vacuum valve V3 anda volume controller 22. including the secondary winding of a transformer23 and volume controlling resistances l4 and 21 in series. Theresistance 44 may be arranged to be adjusted by a pedal d (Fig. 1) whichis connected to an operating lever of varying resistance, while theresistance 21 is constructed to be changed by the key b corresponding tothe pressure of an operator's finger. Thus the gradual volume controlranging from a certain amount to zero and the tremolo play can be easilyattained. The secondary winding of the transformer 2| is connected to afrequency doubler l6 consisting of two rectifier vacuum valves 24, theoutput circuit of which is led to the loud speakers I! and I8 through atrans? former 25, with a variable resistance 43, an'am-r plifier 31 anda volume controller 22 as above described. A and B represent biasbatteries and plate sources of the vacuum valves respectively.

7 In the arrangement shown in Fig. 3, it is clear that the sound whichhas the same frequency but'difierent tone compared with the standardsound of the reed 29 can be produced by the speakers I4 and I5, and atthe same time sound .nection of a speaker lt which reproduces thestandard frequency f itself.= The third way is a series connection oftwo frequency triplers 41, the first stage of which is provided with abranch circuit having a frequency doubler 48. These frequency triplersand frequency doublers are also connected respectively to speakers 49,5B and 5| which produce 3f, iii and 6f respectively.

In the arrangement illustrated in Fig. 3 or 5, when the speakers areoperated simultaneously or selectively, the current of the speakersincludes higher harmonics and multiple frequencies of the microphonecurrent so that the tone composition and octave performance can beeasily attained without so many reeds in a multiple key-board andcomplicated stop mechanisms used in an ordinary pipe organ.

Moreover, if reeds of reed organs, microphones ofelectromagnetic,electrostatic and Reisz types, and speakers of horn andcone types, that is, microphones, sound producing and sound reproducingmechanisms having different characteristic frequency regions may becombined-to the above circuits, then the desired tones of any musicalinstrument can be produced. Inventor's experiments show that the solemnsound of a pipe organ can be composed by using reeds of areed organ asvibrators, of the Reisz types with fiat characteristics as microphonesand of the dynamic cone types which are sensitive to the lowerfrequencies as speakers; the tones of a el'arionet may be also producedif reeds of an organ, condenser type microphones having very tensiblediaphragms and speakers which are sensitive to the intermediatefrequencies of sound wave are used; and tones of a group of flutes arecomposed by changing the above reeds of the reed organ to reeds ofharmoniums, the other parts maintaining unchanged. By suitably combininga number of vibrators, microphones and speakers of differentcharacteristics as above described-to a plurality of electric circuit:including tone changing devices and frequency changers, tones of musicalinstruments with pipes and those of violin groups may be reproduced fromthe natural tones of an organ with only one row of organ reeds.

Fig. 4 shows an arrangement of such a case. A plurality of soundproducing elements 3 having difl'erent characteristic frequency regionsare arranged respectively opposite to corresponding microphones 4 havingdifierent characteristics in the sound proof casing. The output side ofthe microphones, 4 are respectively connected to amplifiers 5 throughtransformers 28, potentiometers 52 for volume control and potentiometers53 for tremolo play at the outside of the sound proof casing. Thetremolo play can, in practice, be attained by sliding the intermediatetaps of the potentiometers 53 by an operators hand.

Connected respectively to the output circuits of the amplifiers 5 areloud speakers it, IS and l1, l8, which have different characteristicfrequency regions. Though only two-systems including the sound producingelement, microphone, electric circuits and loud speakers are illustratedin the drawings, yet in practice a plurality of these systems maypreferably be used. In the above arrangement, any desired musical tonescan be reproduced by either or both of the sound producing elements 3and selectively connecting the loud speakers to the amplifiers 5.

On the performance of the above electric organ, the howling phenomenabetween the microphone 4' and the outer sound sources such as manyspeakers and other orchestras may be effectively obviated since themicrophone i is completely insulated from external sound in the soundproof casing l.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:

1. An electrically operated reed organ comprising a series of reedsarranged on a sound-board, a plurality of magnetically operated valveswhich normally close each of the inlet openings of the enclosed airchamber formed by said sound-board for controlling the operation of saidorgan reeds respectively, a plurality of electromagnets for controllingsaid valves respectively, said valves and electromagnets being disposedinside of said sound-board, a microphone for receiving the sound energyfrom said organ reeds, a soundproof casing for totally enclosing saidsound,- board and microphone, said sound-proof casing having an inletpipe for taking air therein and an exhaust pipe for connecting said airchamber to a blower, a key board arranged outside of said sound-proofcasing for controlling said electromagnets, an amplifier connected tosaid microphone, a tone changing device for producing higher harmonicsof microphone current, means for changing the frequency of saidmicrophone current to its multiple frequencies, a volume controller foradjusting the output current gradually from a certain amount to zero,and a plurality of speakers having peak resonance characteristics atdifierent frequency regions connected to the output side of saidfrequency changaooaaas a irequency changer which is associated with saidamplifier and which consists 01 a plurality of frequency douhlersconnected in series and a plurality of frequency triplers connected inseries, the input circuit of said frequency 5 changer being connected tothe output side of said tone changing device. and a plurality ofspeakers having peak resonance characteristics at diflerent frequencyregions connected to the output circuit oi said frequency doublers andfrequency 10 triplers respectively.

BEIICHI YAMASHITA.

